Exam 18: Quasars and Other Active Galaxies

The major surprise about Cygnus A, one of the first three sources of strong radio emission detected by Grote Reber in the late 1930s, when examined with large optical telescopes, was that it

Synchrotron radiation is produced whenever

Seyfert galaxies are

Double-radio sources, quasars, and BL Lacertae objects are now considered to be the same basic type of object-an accretion disk producing two oppositely directed jets-but they appear to observers to be very different because

Centaurs A is a giant radio galaxy. Its radio emission is primarily from the

What observational fact convinces astronomers that the source of energy in a typical quasar is physically very small?

Which of these is a characteristic of a Seyfert galaxy?

Astronomers believe a supermassive black hole of three billion solar masses exists at the center of the giant elliptical galaxy M87. Which one of these is NOT a piece of evidence used to deduce this?

What is the origin of fast radio bursts?

Observations indicate that BL Lacertae objects are

Which of these statements has NOT provided observational evidence of the existence of supermassive black holes in the centers of galaxies?

What mechanism appears to produce the double-radio sources seen in intergalactic space?

Which of these designations does NOT refer to the shape of a galaxy?

What are the typical characteristics of a quasar in terms of energy generation?

Redshifts revealed the radio source Cygnus A to be moving at 17,000 km/s. At this speed it could not have been a part of the Milky Way Galaxy. At this speed how long would it have taken to cross the whole of the visible Galaxy?

One of the first three astronomical objects detected at radio wavelengths by Grote Reber in the late 1930s was

In observations of a double quasar image produced by gravitational lensing, fluctuations on the intensity of one image appear to be delayed compared with equivalent variations on the other image. Explain.

The redshift of the quasar Cygnus A is about 0.046. In the spectrum of this quasar what is the wavelength of the H_α line in the hydrogen spectrum (in nanometers)? The rest wavelength of the H_α line is 656.3 nanometers.

Where do astronomers find supermassive black holes?

Astronomy with a radio telescope was initiated by